1. Field of Invention
The present invention relates to a projector for forming a projected image by magnifying and projecting luminous flux emitted from a light source via a projection lens after being modulated.
2. Description of Related Art
Recently, the number of environments in which projectors are used has increased, and apart from being used solely for presentations in office meetings or meetings on business trips, projectors are now being used at technical meetings in research and development divisions, etc., for capturing CAD/CAM/CAE data therein in order to magnify and project the data, or at various seminars and learning courses. Projectors are now also being used in school classes where audiovisual education is carried out. The projectors are also used for studying therapeutic methods and for performing medical guidance by projecting medical images and data, such as CT scans and MRI, and they are also used for efficiently addressing attendees at exhibitions or conventions in which a number of people are gathered.
Presently, because projectors are used in various environments, various requirements for the specifications and functions of projectors exist, such as light-weight compact models enhancing portability, high-luminance and high-resolution models enhancing image quality, and value-added models capable of connecting to various digital equipment and mobile tools.
Since further increases in the number of environments in which the projectors will be used is likely, more advanced value-added projectors are being vigorously developed based upon the new environments in which projectors will be used.
In such environments, techniques for protecting the inside of the projector from contamination are under development. It is particularly necessary to protect the various optical elements inside the projector from dust in order to maintain excellent image quality. Therefore, a dust-proof method of using cooling air for cooling these elements is important.
An axial-flow fan used as a cooling fan must be arranged close to the internal elements that need to be cooled, resulting in frequent limitations of the arrangement within the projector. Therefore, the problem arises that the degree of freedom of the design layout of the internal parts, including the fan, is so small that it prevents projector miniaturization.
In a conventional projector, an air-inlet is typically arranged on the bottom face or the top face of an outer case. Accordingly, dust at the set-up position of the projector may be sucked from the bottom face, or dust on the top face may be readily sucked therein. As air is received from the bottom face or the top face by using the axial-flow fan, an airflow resistance accompanied by air receiving is also liable to be generated. Therefore, a comparatively large clearance between the body and the set-up surface needs to be maintained with foot members, etc. Thus, the problem also arises of preventing the apparatus height from being reduced and furthermore preventing projector miniaturization.
It is an object of the present invention to provide a projector capable of reducing costs and promoting miniaturization while making sure that the projector is dust-proof.
A projector according to the present invention includes: a light source; a projection lens; an outer case having an air-inlet formed on the side thereof that receives cooling air, the air-inlet being disposed beside the projection lens; and a sirocco fan that receives air disposed at one of an upper part and a lower part of the projection lens. Luminous flux emitted from the light source is magnified and projected by the projection lens so as to form a projected image after being modulated. An air-inlet of the sirocco fan opposes the projection lens.
In the structure according to the present invention, since the air-inlet is formed on the side of the outer case, the possibility of sucking dust on the set-up place of the projector is reduced, and it is difficult for dust to stick to the periphery of the air-inlet, which enables the projector to be dust-proof without requiring a filter on the air-inlet. Even when a filter is attached thereto, it is difficult for dust to stick to the periphery of the air-inlet, which enables the number of replacements of the filter to be reduced. Under certain circumstances, the replacement of the filter can be eliminated. If so, the replacement structure of the filter is not required.
When the filter or the replacement structure of the filter is not required, the number of parts is reduced, and the structure around the air-inlet can also be simplified, thereby reducing the manufacturing cost.
Since the air-inlet is formed on the side face of the outer case, and the air-inlet of the sirocco fan opposes the projection lens, the air-flow resistance following air receiving can be reduced, which facilitates miniaturization of the apparatus.
Furthermore, the sirocco fan is placed by utilizing a space in an upper part or a lower part of the projection lens which is liable to be a dead space, enabling the internal space to be efficiently used and the degree of freedom of a layout design for other internal elements to be increased, thereby promoting miniaturization of the projector.
In a projector according to the present invention, a duct in the receiving side may be preferably arranged between the air-inlet formed on the side of the outer case and the air-inlet of the sirocco fan. By arranging the duct in the receiving side, the cooling air flows into the air-inlet of the sirocco fan efficiently so as to improve the cooling efficiency of the internal elements.
In a projector according to the present invention, a duct in the exhaust side may be preferably arranged between an air-outlet of the sirocco fan and one of an upper part and a lower part of an optical modulator that modulates the luminous flux. By arranging the duct in the exhaust side, the cooling air can be securely sent without omission to the optical modulator from the air-outlet of the sirocco fan, enabling the cooling efficiency to be further enhanced.
In a projector according to the present invention, a duct in the exhaust side may be preferably arranged between an air-outlet of the sirocco fan and one of an upper part and a lower part of an optical modulator that modulates the luminous flux, and the duct in the receiving side and the duct in the exhaust side may preferably be formed integrally with each other. By such a structure, in addition to the enhancement of the cooling efficiency, the handling of the duct is enhanced due to the integration, facilitating assembly of the duct into the projector.
In a projector according to the present invention, the duct in the exhaust side may preferably be provided with a direction-bending section formed therein that vertically bends the direction of the cooling air delivered from the sirocco fan.
By providing the direction-bending section, the air-flow direction can be vertically bent securely, so that the optical modulator can be more sufficiently cooled.
The direction-bending section may be preferably formed to have a smooth curved shape. This structure enables the cooling air to flow smoothly so as to suppress noises, etc.
Furthermore, any one of the ducts may preferably be provided with a recess formed therein which is adjacent to and opposes the peripheral surface of the projection lens.
Since the projection lens is generally cylindrical, even when the sirocco fan is arranged to be adjacent to the peripheral face of the projection lens, a clearance is created between the sirocco fan and the projection lens. When the duct is provided with the recess having a shape corresponding to that of such a clearance so as to be adjacent to and oppose the projection lens, a space in the vicinity of the air-inlet of the sirocco fan can be certainly secured as a space within the duct, so that the cooling air flows into the air-inlet of the sirocco fan smoothly.